kuvakenno

Kuvakenno, or image sensor, is a semiconductor device that converts incoming light into an electrical signal. It is the central component of most digital cameras, smartphones, scanners, and many scientific instruments, and determines how scenes are captured and represented in digital form.

An image sensor comprises an array of photosensitive pixels. Each pixel’s photodiode collects charge proportional to light exposure; this charge is stored and later converted to a voltage. A color image is produced through a color filter array, commonly a Bayer pattern, with demosaicing applied to recover full color.

The two dominant sensor families are CCD (charge-coupled device) and CMOS (complementary metal-oxide-semiconductor). CCDs transfer charge across the chip to a readout node, while CMOS sensors provide per-pixel amplification and often integrated readout circuitry. In practice, CMOS sensors are now dominant in consumer devices due to lower power and higher integration, though CCDs remain in specialized contexts.

Performance is described by resolution, pixel size, quantum efficiency, dynamic range, and noise. Larger pixels collect more light, improving signal-to-noise and dynamic range but reducing resolution in a given area. Technologies such as back-illumination and stacking improve light sensitivity and speed.

Sensor formats range from mobile-scale to full-frame and larger professional formats. Applications span photography, videography, microscopy, astronomy, and industrial imaging. The first image sensor, a CCD, was developed in 1969 at Bell Labs by Willard Boyle and George Smith; CMOS sensors emerged in the 1990s and now underpin most consumer imaging devices.